The present invention relates to a method and apparatus for marking paper, board and cellulose web rolls at a slitter for the purpose of identifying the rolls during later finishing steps. Such finishing operations include, e.g., roll transport, rewinding, sheeting or other finishing steps and roll packaging.
In the roll handling systems of paper, board and pulp mills, the rolls must be identified during each processing step in order to assure correct deliveries to correct addresses, properly packaged and combined into shipments to correct customers. Rolls ordered from different customers, referred to herein as customer rolls, are processed to customer specifications by slitting from machine rolls at a slitter to specified width and roll diameter, thus fulfilling the customer order of a specified amount of paper or board having a desired width. Generally, a barcode sticker is used for marking rolls made at a slitter. The later process stages are equipped with barcode readers capable of identifying rolls from the information read from the barcode sticker. Currently, the barcode sticker is attached manually on each roll at the slitter. The slitter operator reads the roll set data from the control system display of the slitter in order to identify the rolls discharged from the slitter and next prepares roll identification barcode stickers that are then attached to the rolls by the operator. Typically, a self-adhesive barcode sticker is used that is adhered to the roll end or in some board mills, to the roll wrapper. Alternatively, the identification label can be inserted into the center bore of the roll core or attached by a stapler to the core end. The cost of a single barcode sticker is about US. $ 0.02-0.03 per sticker. In manual placement of barcode stickers, the reliability of the product identification method is chiefly dictated by the discipline conducted by the slitter operators. If good care is not exercised in the attachment of the barcode sticker, it may disappear during shipment, it may become attached to the wrong roll or in an incorrect position or otherwise misplaced . Any of these defects can cause problems in the identification of the roll or a misidentification of the roll, thus resulting in a delay during later handling of the roll. Furthermore, such a conduct is contrary to the principles of quality assurance systems, because the error thus invoked can be detected only in the next processing step and defective products have thus already been able to slip further in the process than is possible in a system based on realtime detection of possible errors. Moreover, the manual method of attaching barcode stickers to the roll ends requires more personnel and may compromise occupational safety at the slitter if the operator fails to follow the discipline of working instructions. For instance, in the handling of rolls it is imperative that the operator not approach the rolls until their movement on the rolling ramp of the slitter is entirely brought to a halt. As even the smallest rolls currently used have a mass of about 200-300 kg and the largest may be from 6 to 8 tons, they cannot be managed manually. Hence, it can be seen that all the work performed at a slitter should be preferably made using automatic roll handling equipment.
The slitter also outputs rolls not necessarily requiring an identification code. Typically, this type of roll is a so-called edge trim roll which is an unwanted roll resulting from, e.g, paucity of customer roll orders or the width mismatch of ordered rolls with the stock web width from which the machine roll is wound. In some mills, these edge trim rolls, which represent a production loss are an everyday problem. The processing of edge trim rolls varies mill by mill. One approach is to identify the edge trim rolls in the same fashion as customer rolls, after which they are launched on the conveyors along with the customer rolls or alternatively, they are rolled forward without an identification sticker or even taken directly to the shredder area for repulping. The same routine is also applied to so-called reject rolls. A reject roll is a rewound roll, initially produced as a customer roll at the slitter, but then found defective due to such a production flaw that prevents its shipment to the original or any other customer.
Slitter roll run data also include information on paired and multiple slit rolls complemented with their identification codes. Typically, paired and multiple rolls are narrow rolls discharged from the slitter and later grouped into a shipment. Roll bundling takes place so that the first roll of the bundle is pushed aside awaiting for the next roll to be included in the bundle. When the next roll arrives, the operator moves the rolls side by side and combines them into a shipping bundle whose structure can be additionally secured by different strapping techniques. Bundling can be carried out either on the mill floor or on conveyors. Paired or multiple rolls to be bundled together may be assembled from a single roll set, two successive sets or a multiplicity of successive sets.
When the customer rolls are marked with identification bar codes in the above-described manner, the mill has to use two parallel coding systems. The roll identification bar code is utilized only during roll handling inside the mill. Additionally, the roll ends are provided with a numeric or alphabetic code serving the paper or board product buyer with information on the roll type and paperi/board grade. The customer-specific roll identification code is entirely ignored in the internal roll handling system of the mill. Obviously, such dual marking of a roll causes extra costs.
It is an object of the present invention to provide a method suited for automatic marking of paper, board and cellulose web rolls at the slitter using the same roll identification system that is used for labelling the rolls with information serving the customer.
The goal of the invention is achieved by providing the roll marking equipment with the identification data related to a roll set, that is, a set of slit rolls leaving the slitter and subsequently transferring the customer rolls away from the slitter area only via the roll marking equipment and simultaneously preventing new rolls from entering the slitter area in any other form except as a new roll set. Thus, the correct identification data for each roll set is available to the marking equipment at all times.
The marking equipment marks a roll automatically with the correct identification data advantageously using the same format as is used in marking the roll with the customer data.
According to one embodiment of the invention, the roll marking equipment is provided with the identification data related to a roll set, that is, a set of slit rolls leaving the slitter and the roll entering the marking station is measured for at least one verification parameter such as roll width, for instance, and if so required, also for such parameters as roll diameter and weight, for instance, whereby also the end inward bulging and roll core stick-out can be detected. The measured verification data is compared with the data of the roll set, wherein it is possible to identify each roll from each set and to check whether the correct roll has entered the marking station. Next, the roll is automatically marked with the roll identification data advantageously using the same format as is used in marking the roll with the customer information. The use of the verification data is not mandatory, but the verification data can be utilized, e.g., for backing the quality assurance system and gathering product parameter data.
The invention offers significant benefits.
By virtue of the invention, it is possible to utilize the same marking as is made on rolls produced for direct shipment to customers also in the internal roll identification system of the mill. Hence, the barcode identification system based on stickers or labels can be omitted, whereby equipment for printing barcode stickers or labels can be disposed with. The identification data to be marked on the rolls can be made simply by printing directly on the roll surface with the help of an ink-jet printer, for instance. Accordingly, the operator need not enter the hazard zone of roll movement for adhering barcode stickers/labels on the roll ends that may sometimes be located very close to each other. On the contrary, the slitter operator can stay in his isolated control room without being compelled to move at all about in the roll transfer area, whereby the occupational safety level is substantially elevated. When the identification data is printed directly on the roll surface, the risk of lost or misplaced identification stickers/labels is eliminated. Also the operation of the roll packaging machine is speeded, because the packaging machine need not print the roll with a separate customer identification data.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are intended solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.